QAM信号的波特率估计

Symbol Rate Estimation for QAM Signal

将传统的信号处理工具———傅里叶变换与小波变换相结合,提出了一种QAM信号波特率提取的新方法。对QAM信号作2次连续小波变换,其小波变换的结果在码元跳变点处出现明显的峰值,其他处都为零。然后再作FFT,则一次谐波谱线(即第2根峰值谱线)的位置恰好位于f=fb处,因此,通过检测第2根峰值谱线位置即可估计出QAM信号的波特率。对高斯白噪声中QAM信号的波特率提取进行了仿真并给出了部分实验结果。

By combining the traditional signal processing tool-FFT with wavelet transform, a new method of baud-rate extraction for QAM signal is put forward in this paper. After two-time continuous wavelet transform of the QAM signal,the result indicates that obvious peaks appear at the dots which the codes change,while the values at other dots are zeros. Then,FFT of the above result,the first harmonic wave spectrum, that is the second spectrum peak, appears just at the position where frequency equal to symbol rate. Therefore, through detecting the position number of the second spectrum peak, the symbol rate can be obtained.The emulation experiment of this arithmetic at the background of white gauss noise has been carried through, and partial experiment results are listed.